Japan revising fuel cycle safety rules

25 July 2013

CORRECTED: An earlier version of this story stated that new rules for research reactors would apply to the Monju unit. This error is corrected below.Draft safety requirements for nuclear fuel cycle facilities and research reactors have been approved by Japan's Nuclear Regulation Authority (NRA). Meanwhile, restart inspections are to proceed at four power reactors.

While revised safety regulations covering the restart of nuclear power reactors idled as a result of the 2011 Fukushima accident came into force on 8 July, the NRA's commissioners have now approved the draft criteria for new safety regulations for the country's fuel cycle facilities and research reactors.

The new safety standards will be applied to the country's fuel fabrication plants - including the mixed-oxide (MOX) fuel facility currently under construction at Rokkasho - and its reprocessing facilities. Used fuel and radioactive waste storage and disposal facilities will also be subject to the revised rules, as will research reactors (except the Monju prototype fast breeder reactor) and nuclear fuel research centres.

The requirements will vary from facility to facility, but generally include reinforcement measures against natural threats such as earthquakes and tsunamis, and in some cases tornadoes, volcanoes and forest fires. Severe accident countermeasures will also be required at the country's fuel fabrication and reprocessing facilities. These include measures against terrorist attacks, hydrogen explosions, criticality accidents, fires resulting from solvent leaks and vaporization of liquid waste.

The specific details of how each of the requirements will be met have yet to be determined. The draft regulations are open to public comment until mid-August and the finalized rules will come into force by December 18.

Reactor inspections

Since the new safety requirements for power reactors were launched, four Japanese utilities - Kansai, Hokkaido, Shikoku and Kyushu - have applied for permission to restart twelve of the country's non-operating reactors.

The NRA has now announced that it will begin safety inspections at four of these units: Hokkaido's Tomari unit 3, Shikoku's Ikata unit 3, and units 1 and 2 of Kyushu's Sendai plant.

The regulator requested that Hokkaido submit additional information before checks will be carried out at units 1 and 2 at Tomari. In addition, the NRA said that it will not conduct inspections of Kansai's Ohi 3 and 4 units - the only two reactors that have been permitted to resume operations - until an ongoing investigation is completed into seismic fault lines at the site. Ohi 3 and 4 are set to continue in operation until September when they will enter their next scheduled maintenance outage.

The NRA has also requested Kansai conduct additional seismic studies and tsunami risk calculations at its Takahama 3 and 4 units before it will start inspections of those reactors. No decision was announced on when safety inspections would be carried out at Kyushu's Genkai 3 and 4.